This lesson describes how the surfaces in insects, fish and mammals are adapted for gas exchange. The PowerPoint and accompanying worksheets have been designed to cover the detail of point 4.3 (i) of the Edexcel A-level Biology B specification. The lesson has been intricately planned to challenge the students on their understanding of the surface area to volume ratio (as covered in topic 4.1) and to make direct links to upcoming lessons on the transport systems in humans. The lesson begins by explaining that single-celled organisms are able to diffuse oxygen and carbon dioxide across their body surface but that as organisms increase in size and their SA/V ratio decreases, they need adaptations at their gas exchange surfaces to be able to obtain the oxygen to meet their metabolic demands. This leads into the next part of the lesson which describes the roles of the following structures in insects and bony fish: spiracles, tracheae, tracheoles and tracheole fluid operculum, gill arch, gill filaments and lamellae The next task challenges the students to use their knowledge of topics 1, 2 and 3 to come up with the letters that form the key term, countercurrent flow. This is a key element of the lesson and tends to be a principle that is poorly understood, so extra time is taken to explain the importance of this mechanism. Students are shown two diagrams, where one contains a countercurrent system and the other has the two fluids flowing in the same direction, and this is designed to support them in recognising that this type of system ensures that the concentration of oxygen is always higher in the oxygenated water than in the blood in the lamellae. As the alveoli as a structure of gas exchange was introduced at GCSE, this final part of the lesson has been written to challenge the recall of that knowledge and to build on it. The main focus is the type of epithelium found lining the alveoli and students will discover that a single layer of flattened cells known as simple, squamous epithelium acts to reduce the diffusion distance. Again, students will have met this in a lesson in topic 2 on specialised cells (and tissues) so a number of prior knowledge checks are used alongside current understanding checks. The following features of the alveolar epithelium are also covered: Surface area Moist lining Production of surfactant The maintenance of a steep concentration gradient As a constant ventilation supply is critical for the maintenance of the steep concentration gradient, the final task considers the mechanism of ventilation

This lesson describes how only part of a cell’s DNA is translated and explains how the potency of a stem cell determines its ability to specialise. The engaging and detailed PowerPoint and accompanying resources have been planned to cover all of the content in point 8.2.1 of the AQA A-level biology specification. The lesson begins by challenging the students to recall any existing knowledge of stem cells, to check that they remember that these cells differentiate, before the concept of cell potency is introduced to allow them to recognise that not all cells can differentiate into the same amount of cell types. A quick quiz is used to introduce pluripotency, unipotency, totipotency and multipotency before they are challenged to use their understanding of language to order these along the potency continuum. Beginning with totipotency, time is taken to go through details of each of these cell types, including where these cells are located. During the section of the lesson considering pluripotency, induced pluripotent stem cells are discussed and their potential for use in regenerative medicine is explored. Understanding checks through exam-based questions are embedded throughout the lesson (as well as the answers) to allow students to assess their current understanding and to address any gaps immediately. There are also prior knowledge checks so students can link to other topics from the specification and there is a maths in biology question so their mathematical skills are challenged in line with that element of the course.

This lesson describes how epigenetic changes like DNA methylation and histone modification can modify the activation of certain genes. The PowerPoint and accompanying resources have been planned to cover points 3.14 ii & iii of the Pearson Edexcel A-level biology (Salters-Nuffield) specification. The lesson begins by introducing the prefix epi- as meaning on or above in Greek to allow students to recognise that epigenetics refers to changes in gene function due to factors beyond the genetic code. Moving forwards, they will learn that DNA methylation involves the attachment of a methyl group to cytosine and will come to understand how this inhibits transcription. They are challenged to recognise the pathogenesis of atherosclerosis through a variety of tasks before reading through a source detailing the results of a study between this cardiovascular condition and DNA methylation. The remainder of the lesson considers how the acetylation of histone proteins affects the expression of genes. Understanding and prior knowledge checks are embedded throughout the lesson (along with the answers) to allow the students to assess their progress on this topic and to encourage them to make links to the content of topics 1 - 2.

This detailed lesson describes the processes of PCR and electrophoresis to allow students to understand how gene sequencing can be used. The engaging PowerPoint and accompanying resource have been planned to cover the content of point 7.1 of the Edexcel A-level biology B specification. The lesson begins by comparing the number of genes in the genome with the number of base pairs, to allow students to learn that the bases in the genes only accounts for about 1.5% of the genome. This challenges them to recall that most is non-coding DNA, and the importance and usefulness of these sections are explored during the lesson. Moving forward, a step-by-step guide describes the key steps in the polymerase chain reaction, and time is taken at each step to qualify the fine details such as the use of Taq polymerase instead of human DNA polymerase. The remainder of the lesson focuses on the various uses of these DNA samples once they’ve been amplified by the PCR. The steps of the electrophoresis process are described and students will see how DNA profiling can be used in forensic science to identify criminals and for paternity tests. Understanding and prior knowledge checks are found throughout the lesson, along with the answers, to allow students to assess their grasp of the current topic as well as their ability to identify the links with previously covered topics.

This lesson guides the students through the stages of the Krebs cycle, describing how ATP and reduced NAD are produced and carbon dioxide released. The PowerPoint and accompanying resource have been planned to cover the content of topic 3 point [c] of A2 unit 3 as set out in the WJEC A-level biology specification. As shown on the cover image, the lessons starts with a challenge, where students are tasked with recognising that the connection is biological cycles. A prior knowledge check is used to challenge their recall of the mitochondria as the site of aerobic respiration and then to identify the matrix as the site for this particular stage. Moving forwards, the 6 steps of the cycle are explored, and time is taken to consider how dehydrogenation and decarboxylation lead to the reduction of NAD and the release of carbon dioxide, and how ATP is produced by substrate-level phosphorylation. A series of exam-style questions check their understanding, and this includes a link to the next stage and the electron transport system. The answers to all knowledge checks are embedded into the PowerPoint to allow the students to assess their progress.

This fully-resourced lesson describes the inheritance of genes with loci on the X chromosomes and considers biological examples. The detailed PowerPoint and accompanying resources have been designed to cover point 2.15 (ii) of the Edexcel International A-level specification and focuses on the inheritance of red-green colour blindness and haemophilia in humans Key genetic terminology is used throughout and the lesson begins with a check on their ability to identify the definition of homologous chromosomes. Students will recall that the sex chromosomes are not fully homologous and that the smaller Y chromosome lacks some of the genes that are found on the X. This leads into one of the numerous discussion points, where students are encouraged to consider whether females or males are more likely to suffer from sex-linked diseases. In terms of humans, the lesson focuses on haemophilia and red-green colour blindness and a step-by-step guide is used to demonstrate how these specific genetic diagrams should be constructed and how the phenotypes should then be interpreted. The final task of the lesson challenge the students to apply their knowledge to an exam question about chickens and how the rate of feather production in chicks can be used to determine gender. All of the tasks are differentiated so that students of differing abilities can access the work and all exam questions have fully-explained, visual mark schemes to allow them to assess their progress and address any misconceptions

This fully-resourced lesson describes the action of enzymes as biological catalysts and explains how their specificity is related to their 3D structure. The engaging PowerPoint and accompanying resources have been designed to cover points 2.10 (i) and (ii) of the Pearson Edexcel A-level Biology A specification but also introduces some examples of intracellular and extracellular enzymes to prepare students for the next lesson which covers 2.10 (iii). The lesson has been specifically planned to tie in with related topics that were previously covered such as protein structure, globular proteins and intracellular enzymes. This prior knowledge is tested through a series of exam-style questions along with current understanding and mark schemes are included in the PowerPoint so that students can assess their answers. Students will learn that enzymes are large globular proteins which contain an active site that consists of a small number of amino acids. Emil Fischer’s lock and key hypothesis is introduced to enable students to recognise that their specificity is the result of an active site that is complementary in shape to a single type of substrate. Time is taken to discuss key details such as the control of the shape of the active site by the tertiary structure of the protein. The induced-fit model is described so students can understand how the enzyme-susbtrate complex is stabilised and then students are challenged to order the sequence of events in an enzyme-controlled reaction. The lesson finishes with a focus on ATP synthase and DNA polymerase so that students are aware of these important intracellular enzymes when learning about the details of respiration and DNA replication.

This lesson describes how enzymes can be immobilised in calcium alginate and compares their activity against enzymes that are free in solution. The PowerPoint and the accompanying resources have been designed to cover point 3.2 (d) of the CIE A-level Biology specification. The lesson has been planned to challenge the students on their ability to apply knowledge to a potentially unfamiliar situation. A series of exam-style questions which include “suggest” and “describe and explain” questions are used throughout the lesson and these will allow the students to recognise the advantages and disadvantages of a particular method. Although the alginate method is the only one referenced in this specification point, the adsorption and covalent bonding methods are introduced and then briefly analysed to allow students to understand that a matrix doesn’t involve these bonds which could disrupt the active site. The remainder of the lesson introduces some actual examples of the use of immobilised enzymes with the aim of increasing the relevance. Please note that this lesson has been written to explain the effect of immobilisation on enzyme activity. The practical element of carrying out the investigation is described in a separate lesson.

This lesson explains how the polymerase chain reaction (PCR) is used to amplify DNA. The PowerPoint has been designed to cover point 6.17 of the Edexcel International A-level Biology specification. A quick quiz competition is used to introduce the PCR abbreviation before students are encouraged to discuss the identity of the enzyme involved and to recall the action of this enzyme. Students will learn that this reaction involves cyclical heating and cooling to a range of temperatures so the next part of this lesson looks at these particular temperatures so the important parts of each of the steps can be understood. Time is taken to examine the key points in detail, such as the specific DNA polymerase that is used and how it is not denatured at the high temperature as well as the involvement of the primers.

This lesson looks at the detailed structure of DNA and builds on the knowledge from topic 1 to explain how this nucleic acid differs in the nucleus, mitochondria and chloroplasts of eukaryotic cells and in prokaryotic cells. Both the engaging PowerPoint and accompanying resources have been designed to cover the first part of point 6.1 (b) of the CIE International A-level Biology specification. As well as focusing on the differences between the DNA found in these two types of cells which includes the length, shape and association with histones, the various tasks will ensure that students are confident to describe how this double-stranded polynucleotide is held together by hydrogen and phosphodiester bonds. These tasks include exam-style questions which challenge the application of knowledge as well as a few quiz competitions to maintain engagement.

This detailed lesson describes how the movement of water between solutions and cells has differing effects on animal and plant cells. Both the PowerPoint and accompanying resources have been designed to cover specification points 4.2 (a) and (f) as detailed in the CIE International A-level Biology specification. It’s likely that students will have used the term concentration in their osmosis definitions at GCSE, so the aim of the starter task is to introduce water potential to allow students to begin to recognise osmosis as the movement of water molecules from a high water potential to a lower potential, with the water potential gradient. Time is taken to describe the finer details of water potential to enable students to understand that 0 is the highest value (pure water) and that this becomes negative once solutes are dissolved. Exam-style questions are used throughout the lesson to check on current understanding as well as prior knowledge checks which make links to previously covered topics such as the lipid bilayer of the cell membrane. The remainder of the lesson focuses on the movement of water when animal and plant cells are suspended in hypotonic, hypertonic or isotonic solutions and the final appearance of these cells is described, including any issues this may cause.

This lesson describes the function of transcription factors in eukaryotes and uses the lac operon to explain the control of protein production in a prokaryote. The detailed PowerPoint and accompanying resources have been designed to cover points 16.3 (b, c & d) as detailed in the CIE A-level Biology specification and also includes a description of how gibberellin breaks down DELLA protein repressors, allowing transcription to be promoted. This is one of the more difficult concepts in this A-level course and therefore key points are reiterated throughout this lesson to increase the likelihood of student understanding and to support them when trying to make links to actual biological examples in living organisms. There is a clear connection to transcription and translation as covered in topic 6, so the lesson begins by reminding students that in addition to the structural gene in a transcription unit, there is the promoter region where RNA polymerase binds. Students are introduced to the idea of transcription factors and will understand how these molecules can activate or repress transcription by enabling or preventing the binding of the enzyme. At this point, students are challenged on their current understanding with a series of questions about DELLA proteins so they can see how these molecules prevent the binding of RNA polymerase. Their understanding is then tested again with another example with oestrogen and the ER receptor. The final and main section of the lesson focuses on the lac operon and immediately an opportunity is taken to challenge their knowledge of biological molecules with a task where they have to spot the errors in a passage describing the formation and breakdown of this disaccharide. Students will be able to visualise the different structures that are found in this operon and time is taken to go through the individual functions. A step by step guide is used to walk students through the sequence of events that occur when lactose is absent and when it is present before they are challenged to apply their understanding to an exam question.

This lesson describes the relationship between the specialised features of the mammalian egg and sperm and their functions. The PowerPoint and accompanying resources have been designed to cover point 3.11 of the Edexcel International A-level Biology specification and includes a focus on the acrosome in the head of the sperm and the zona pellucida in the egg The lessons at the start of topic 3 (Cell structure, Reproduction and Development) described the ultrastructure of eukaryotic cells, so this knowledge is referenced throughout the lesson and the students are challenged on their recall and understanding through a range of prior knowledge checks. For example, two of the exam-style questions that are included in the resources challenge the students to explain why a sperm cell is classified as an eukaryotic cell and to recognise the centrioles and the nucleus from structural descriptions. Along with the mitochondria, time is then taken to discuss and to describe the role of these organelles in relation to the function of the sperm cell. When considering the fusion of the haploid nuclei to form a diploid nucleus in the nucleus, links are made to the upcoming topic of mitosis and the significance of this form of nuclear division. The importance of the enzymes that are found inside the acrosome is emphasised and this leads into the second half of the lesson where the layers surrounding the plasma membrane of the egg cell (corona radiata and zona pellucida) are examined The final part of this lesson has been specifically planned to prepare the students for the next lesson in topic 3, where the acrosome reaction, cortical reaction and the fusion of nuclei that are involved in fertilisation are described

An engaging and informative lesson presentation (30 slides) that looks at some of the uses of stem cells in medicine. The lesson begins by challenging the students to define some key terms such as undifferentiated which are associated with these cells. Moving forwards, students will look at the uses of embryonic stem cells including in the treatment of Parkinson’s disease and for tests in drug trials. Students are challenged to consider for homework why the uses of these cells remains controversial. This lesson is designed for GCSE students

This lesson has been designed to cover the content of the 1st part of specification point 6.1.2 of the AQA A-level Biology specification which states that students should know the basic structure of a Pacinian corpuscle and be able to use its function as a representation of sensory receptors. By the end of the lesson students will understand that sensory receptors respond to specific stimuli and how a generator potential is established. The lesson begins by using a quiz to get the students to recognise the range of stimuli which can be detected by receptors. This leads into a task where the students have to form 4 sentences to detail the stimuli which are detected by certain receptors and the energy conversion that happen as a result. Students will be introduced to the idea of a transducer and learn that receptors always convert to electrical energy which is the generator potential. The remainder of the lesson focuses on the Pacinian corpuscle and how this responds to pressure on the skin. The involvement of sodium and potassium ions is introduced so discussions on how the membrane potential changes from resting potential in the establishment of a generator potential are encouraged. This lesson has been written for students studying on the AQA A-level Biology course and ties in nicely with other uploaded lessons which cover the content of topic 6

This lesson describes the sequence of events that occur during the phagocytosis of pathogens and the subsequent destruction by lysozymes. The engaging and detailed PowerPoint and accompanying resources have been primarily designed to cover the second part of point 2.4 of the AQA A-level Biology specification but includes an introduction to antigen-presentation so that the students are prepared for upcoming lessons on the cellular and humoral responses. At the start of the lesson, the students are challenged to recall that cytosis is a suffix associated with transport mechanisms and this introduces phagocytosis as a form of endocytosis which takes in pathogens and foreign particles. This emphasis on key terminology runs throughout the course of the lesson and students are encouraged to consider how the start or end of a word can be used to determine meaning. The process of phagocytosis is then split into 5 key steps and time is taken to discuss the role of opsonins as well as the fusion of lysosomes and the release of lysozymes. A series of application questions are used to challenge the students on their ability to make links to related topics including an understanding of how the hydrolysis of the peptidoglycan wall of a bacteria results in lysis. Students will be able to distinguish between neutrophils and monocytes from a diagram and at this point, the role of macrophages and dendritic cells as antigen-presenting cells is described so that it can be used in the next lesson. The lesson concludes with a brief introduction to lymphocytes so that initial links between phagocytosis and the specific immune responses are made.

This revision lesson contains an assessment of 20 multiple-choice questions and a PowerPoint with the answers and related key points from the specification. The 20 questions have been written to cover the content of topic 4 of the AQA A-level biology specification, providing the students with an opportunity to assess their understanding and highlight those areas which need further attention. All 7 sub-topics of topic 4 are covered by at least one question and there are several questions which challenge mathematical skills, which aligns with the high mathematical content of the final assessments.

This fully-resourced REVISION lesson has been written to challenge the students on their knowledge of the content of topic 8 (Transport in mammals) of the CIE International A-level Biology specification. The engaging PowerPoint and accompanying resources will motivate the students whilst they assess their understanding of the content and identify any areas which may require further attention. The wide range of activities have been written to cover as much of the topic as possible but the following specification points have been given particular focus: The significance of the oxygen dissociation curves at different concentrations of carbon dioxide (The Bohr effect) The role of haemoglobin in carrying oxygen The role of haemoglobin in carrying carbon dioxide Draw the structures of red blood cells, neutrophils, monocytes and lymphocytes The relationship between the structure and function of a capillary The internal structure of the heart and its associated blood vessels Explain how heart action is initiated and controlled The pressure changes of the cardiac cycle The relationship between the structure and function of arteries and veins The double, closed circulatory system of a mammal Quiz rounds such as “Does this FLOW correctly” and “YOU DO THE MATH” are used to test the students on the finer details of their knowledge of the blood vessels and numerical facts